The age old problem of electrical interference... HELP...

Ok friends I'm having an issue in that I'm getting a dreadful sound through my Mackie desk when the gains are really pushed, something I do quite often for some distortion. Hiss I can handle, but his noise is in relation to the computer in that you can "hear" when it's processing and also when you scroll on the mouse. My setup is as follows:

iMac intel new model

connected via Firewire to >>>>

Mackie Onyx 400f

connected via 1/4" jack cables to >>>>

Mackie 1402 VLZ mixer

connected via 1/4" to XLR to >>>>

Genelec monitors.

On a mission to isolate this noise I originally thought it might be to do with the Mackie and it's firewire cable. So as a simple test I simply connected the monitors directly to the interface and there was no noise at all as I expected. So that rules out the cabling at least to the monitors I assume?

Now I'm a little stumped. I'm not too up on my cable knowledge, nor am I too informed of how well this room is grounded. But in an attempt to alleviate these problems I have tried to give each component a seperate power supply but still to no avail.

Any ideas are greatly welcomed.

Speakers too close to the screen?

Also, do you have an MPC? I used to get this problem when my MPC's USB cable was connected to the computer while the MPC was on. Somewhere between building a new computer and updating to Windows 7, it went away!

Thanks for the reply Hellfire. I do have an MPC but that's not included in my current set up, when I do use it it simply runs through the mixer. Positioning of the monitors doesn't seem to make any difference at all.

I'm wondering if it's perhaps down to unbalanced cables from the Mackie interface to the mixer but I don't see how I'd still get that computer processing noise.

Shielded cables are always good to have no matter what your situation is. Not just audio but also usb, firewire, and electrical. Also, arranging the cables by keeping electrical, audio, and data separated as much as possible should help too. These are all practical solutions to most interference. However, you mentioned that the only interference you're getting is the sounds the computer makes, which reminded me of a similar experience I've had with my headphones:

I've noticed that my headphones cable can pick up the sounds of a hard drive writing and spinning whenever the cable was pressed against the work desk. It could also pick up my bass guitar whenever the cable was resting on the strings. It might be a long shot, but see if keeping the 1/4" cables off the desk or decouple the imac from the desk with a riser or iso pad will solve the problem.

scoobylol wrote:I'm wondering if it's perhaps down to unbalanced cables from the Mackie interface to the mixer but I don't see how I'd still get that computer processing noise.

By connecting the monitors directly to the interface, you've already eliminated the interface, firewire cable, and monitor cables as potential sources of the problem. So you're on the right track.

Thanks Ocular, I've been reading up on various options regarding balanced cables, and my next option will be to try those from the interface to the mixer.

I've also confirmed that it's not a grounding issue with the mixer. Balanced cables here I come...

scoobylol wrote:Thanks Ocular, I've been reading up on various options regarding balanced cables, and my next option will be to try those from the interface to the mixer.

I've also confirmed that it's not a grounding issue with the mixer. Balanced cables here I come...

Scoob I've got a similar setup, but my Mackie mixer is analog and it's a Mac Pro where the monitor is separate, so I actually have a bit more cabling. I use balanced cables, but had to use a set of unbalanced the other day as they were the only extras I had. Even one set of unbalanced thrown in caused interference throughout the whole chain. It sounds weird but if you can't help but have cables in proximity to each other, try to make them cross at 90 degree angles, it seems less prone to interference than when the cables are parallel. ( I mean those dangling ones you can't really move too much,)

Again thanks Meta, I appreciate the feedback and advice. My cabling is a complete disaster at the moment as I'm trying to rearrange. Although that noise has always been there I've noticed.

My 1402 is also analogue

Had the Emu e6400 Ultra out today because I've simply not used it in so long (in all honesty I've never actually learned to use it to it's full potential something which I'm currently trying to remedy).

Anyway, standard 808 kick into the Emu, low pass filter, bit of experimentation with the envelope. Out through the mixer with the trim set to full... instant old Dillinja bass sounds.

http://www.youtube.com/watch?v=OEcVXsLyiWg

You might enjoy this Meta. Two of my heroes Fracture and Neptune using that to devastating effect!

EDIT: http://www.youtube.com/watch?v=yheX4yrOOQI

Part 2 is more relevant as they talk you through the exact process... check Fractures' screw face when those bass notes play. Too funny, because we know we ALL have that face haha.

Thanks for the link Scoob. Watching it now.

I'm thinking of re-cabling everything today, but maybe I should just live with the slight hiss I have now. I've tried the same as you did, monitors straight from the interface, dead silent. But I've got an RME Multiface II, which doesn't have a dedicated Hardware volume control. I hate to have to rely on software volume controls if something goes haywire. Output from the mixer is better for me to, so I can use my MPC's and keyboards without the PC hooked up.

E-MU e6400, nice. You've got me inspired, I think I'm gonna hook up my ASR10 today.

To be honest hiss wouldn't bother me, neither does a touch of hum because it's really not overly audible, but the second I push the gain on this thing the noise is over-powering.

Just to confirm I've actually run loads of other stuff through the mixer, such as synths etc... and there's no noise at all. I've tested all the inputs too just to ensure it wasn't a couple of dodgy channels. But same old... so I'm definitely starting to narrow it down.

Meta if you like that video then definitely check out their tunes too. Their label is called Astrophonica, and their music is mind-blowing. They recently released a tune called Customtone which featured one of their dads playing lap guitar on it! What I love most about these guys is that they're making such forward-thinking music, based on all the old jungle pioneers techniques. Just shows how relevant hardware still is IMO. I own most of their work on vinyl and their mixdowns are superb aswell. If I ever achieve anything like their sound aesthetic one day I'll be very proud of myself haha.

Yeah please hip me to any Jungle/Breaks style stuff. I like it all, but I'm not very knowledgeable about the genres, especially more recent stuff. I listen to a lot of European dub (G-Corp, Al-Haca, Stereotyp, DubbleStandart etc.), so I only usually hear other stuff when it crosses it over with that genre.

Definitely sounds like an unbalanced cable ruining your day. They're prone to interference/distortion crackling when the gain is raised.

DEFINITELY need balanced cables. And definitely keep power wires away from audio cables. If they must cross, make them cross at a 90 degree angle of each other (like a +) so they aren't running adjacent, if possible. If you have flourescent lighting, it can cause issues as well, although mine doesn't!

I had exactly the same problem if the noise sounds like an old modem & when you move the mouse the noise changes a bit.

I had a Macmini & a FW Saffire LE. I kept sending the LE back to focusrite & everything, had the tech lads pulling their hair out because it was supposed to be uber fidelity & it clearly wasn't. Tried all the balanced cable stuff & cable routing but it clearly wasn't working.

Turned out that what the Macmini called 0volts & what the Saffire called 0volts on the Firewire were two totally different things.

The solution was to get a 6pin to 4pin converter and a 4pin to 6pin for the firewire cable. That took out the power wires from the firewire cable. Then powered the Saffire Le from an external supply.

The result :- utter & total perfection. Faders were full up on my Makie 1402 & still couldn't here a single squeek.



The same sort of thing happens with lots of laptops with USB interfaces, then you unhook the power & run off battery & problem solved.

LZ Roberts wrote:I had exactly the same problem if the noise sounds like an old modem & when you move the mouse the noise changes a bit.

I had a Macmini & a FW Saffire LE. I kept sending the LE back to focusrite & everything, had the tech lads pulling their hair out because it was supposed to be uber fidelity & it clearly wasn't. Tried all the balanced cable stuff & cable routing but it clearly wasn't going to work.

Turned out that what the Macmini called 0volts & what the Saffire called 0volts on the Firewire were two totally different things.

The solution was to get a 6pin to 4pin converter and a 4pin to 6pin for the firewire cable. That took out the power wires from the firewire cable. Then powered the Saffire Le from an external supply.

The result :- utter & total perfection. Faders were full up on my Makie 1402 & still couldn't here a single squeek.



The same sort of thing happens with lots of laptops with USB interfaces, then you unhook the power & run off battery & problem solved.

LZ my interface is actually already powered externally from the mains, not via phantom power supplied by the iMac or what have you. But thanks for the reply dude it's an interesting thought. I think however if it was a problem between the interface and the iMac I'd get the noise at all times even when the monitors were connected directly to the interface. Again thanks for the reply though dude.

Hellfire, cheers for that. If I hadn't won an s3000 this morning on eBay I'd be out right now investing in cables... but you know, you have to get your priorities right

LZ Roberts wrote:I had a Macmini & a FW Saffire LE. I kept sending the LE back to focusrite & everything, had the tech lads pulling their hair out because it was supposed to be uber fidelity & it clearly wasn't.

What are Focusrite like to deal with? I need to give them a call early next week...

My pro 24 was giving me shit before I upgraded to Lion, but now it's given up the ghost completely.

I wouldn't be surprised at all if it turns out to be a cable issue or something daft like that, because I've updated the drivers and checked the obvious things. On the plus side I'm getting quite efficient at editing audio and sequences just with my laptop.

DJ Hellfire wrote:Speakers too close to the screen?

Also, do you have an MPC? I used to get this problem when my MPC's USB cable was connected to the computer while the MPC was on. Somewhere between building a new computer and updating to Windows 7, it went away!

I had this exact issue. i unplug the usb when im not using it.